What events led to v- e day and v- j day?

Victory in Europe Day or V-E Day (May 8, 1945) marked the Nazi Germany's surrender to the Allies. It happened when Adolf Hitler, Nazi Germany's leader, committed suicide during the Battle of Berlin on April 30, 1945. 
Victory over Japan Day or V-J Day marked the day that the Imperial Japan surrendered in World War II. It happened after the US dropped two atomic bombs on Hiroshima and Nagasaki and after Russia declared war on Japan.